The present invention relates to an outboard motor, comprising an internal combustion engine, for propelling a ship, having an air-guiding system which is effective by way of a covering hood surrounding surfaces of the internal combustion engine and auxiliary units.
An internal combustion engine known from U.S. Pat. No. 6,302,749 B1 operates as an outboard motor for propelling a watercraft. The internal combustion engine is surrounded by a covering hood which delimits an interior. To ventilate and vent the interior, the covering hood, which extensively encases the internal combustion engine, is provided with inlet and outlet devices for airflows moving in the interior and serving to act on housing surfaces of the internal combustion engine. The internal combustion engine comprises a vertical crankshaft, which interacts with a plurality of pistons and which drives balance shafts at an upper end region by way of an endless drive. An alternator with a vertical axis of rotation is provided with a fan, which ventilates and vents the interior of a hood-like endless drive covering.
German document DE 102 05 109 B4 describes an outboard motor provided with a vertically oriented crankshaft and a plurality of auxiliary units mounted on an outer side of a machine housing of the outboard motor. A covering hood encases the outboard motor and the auxiliary units. Air inlet slots are provided on a rear side of the covering hood and interact with an adjoining air-channeling device. The air-channeling device ensures that fresh air is channeled into an upper and a lower region of the interior of the covering hood or to the machine housing and to the auxiliary units.
It is an object of the invention to design an internal combustion engine for an outboard motor for propelling a ship in which an air-guiding system is provided in the interior of a covering hood which surrounds the internal combustion engine. The air-guiding system serves for supplying cooling air and intake air for the internal combustion engine and setting benchmarks in this respect. However, it should also be ensured here that the air-guiding system can be implemented using reasonable means.
According to the invention, this object is achieved by the features claimed. Further features of the invention are set out in dependent claims.
Advantages primarily achieved by the invention are that the air-guiding system of the outboard motor, in conjunction with the internal combustion engine, clad by way of the covering hood, has an exemplary function and is easily implemented. Air flows are channeled in an ingenious manner via an inlet opening in the direction of the interior of the covering hood in such a way that these air flows are separated close to the inlet opening into first partial air flows and second partial air flows. In this context, it should be emphasized that the air-guiding system in the covering hood comprises a first channeling device for the first partial air flows and a second channeling device for second partial air flows. It is advantageous that the first partial air flows are fed as intake air to the intake system of the internal combustion engine and that the second partial air flows act in a cooling manner, with the aid of the fan, on the surfaces of said internal combustion engine and auxiliary units heated by the operation of the internal combustion engine. It is technically favorable here that the air flows heated by the surfaces of the internal combustion engine and the auxiliary units are conveyed by the fan and a third channeling device as exhaust air via an outlet opening in the covering hood to an outer side of the latter or into the atmosphere.
It is structurally simple to realize arranging the inlet opening on the vertical hood wall in the upper end region of the covering hood, with the inlet opening being adjoined by the distributing device, which optimizes the air-guiding system, in the covering hood. By virtue of the distributing device, the first partial air flow and the second partial air flow are guided into the first channeling device and the second channeling device, respectively. By way of example here, the first channeling device forms, with an upper hood portion of the covering hood, a duct region which is connected by an outlet region,
The outlet region, for example, may be horizontally oriented, and can have a quadrangular shape and connect to a corresponding inlet region toward the intake system. An ingenious configuration is provided in that, to open the covering hood, the outlet region and the inlet region can be separated from one another, which regions interact with one another with the interposition of an annular sealing body. A noteworthy feature is that the inlet region is connected to a collecting tank which is structurally combined with the compressor of the turbocharger device connected to the intake system.
One feature is a design in which the second partial air flows are channeled via the second channeling device by way of the vertical duct in the direction of the underside of the internal combustion engine and pass from there via the overflow region into the interior of the covering hood, so that the second partial air flows have a heat-reducing influence on the surfaces of the internal combustion engine and of the auxiliary units. As a development here, the duct is formed, on the one hand, by the hood portion of the vertical hood wall and, on the other hand, by boundary portions of the insert of the covering hood. In addition, it is advantageous that the duct region and the insert are connected to the covering hood by adhesive bonding, screwing, or the like.
One feature of the invention is that the fan is driven by way of the vertical crankshaft which projects beyond the upper side of the internal combustion engine. The effect of the air-guiding system is optimized by the fact that, as viewed in the direction of travel of the ship, the inlet opening is arranged adjacent to the rear hood wall and the fan is arranged on the crankshaft close to the front hood wall. The invention is enhanced by the fact that the first crankshaft, which drives the fan forms, together with the second crankshaft, which extends parallel to the first crankshaft, form a crankshaft system of the internal combustion engine in which the crankshafts are in operative connection with at least one reciprocating piston via two connecting rods. The latter is improved by the fact that the crankshafts, which are arranged transversely to the direction of travel on both sides of a center longitudinal plane, have first and second flywheels at their upper ends which project beyond the upper side of the internal combustion engine. The flywheels, as viewed in the vertical direction of the crankshafts, are arranged offset to one another and overlap one another in certain regions, the fan being structurally combined with the upper first flywheel.
Preferably, the first flywheel with fan and the second lower flywheel are covered by a first upper hood portion and a second lower hood portion, respectively, which are formed as a fan-flywheel covering which is produced from one piece or consists of a plurality of parts. In one preferred embodiment, the first hood portion, which dads the fan, is provided with the third channeling device, which has an approximately spiral tangential portion of the fan-flywheel covering. The tangential portion guides the exhaust air conveyed by the fan by way of the outlet opening to the outer side of the covering hood or into the atmosphere. Finally, the fan has an impeller system with mixed flow, radial flow or the like, which can be readily implemented.